I read a previous question asked and answered and I have a follow-up
question.  (http://answers.google.com/answers/threadview?id=196127)

In the above questions? answer, can you explain more about the statement: 

?And, they have access to a nationwide database
that is pretty comprehensive regarding a person's health history,
which means they are likely to discover your omission during
application process anyway.?

If have no health insurance and have been treated for an illness ? is
this traced via my SS# ?  What about simple lab work/blood work
submitted via my private doctors office where I paid cash.  Is that
too traceable via a SS# or by some other means?

Here is my situation:  

I am 37, single, fit, workout 5 times a week, don?t smoke, I livei n
Dallas Texas and I?m very healthy for the most part.  I have not
worked for an employer who provided health insurance for over 10
years.  I am thinking it's time to get insurance and have decided to
apply.

I have been to both a hospital with a odd case of low platelet count
that turned out to be nothing and I see my doctor about ever 2 years
to have simple lab work done to check on my Hep B. (chronic, but
inactive).  I also used the State health Department while I was
unemployed for about a year and I was feeling depressed.  They
misdiagnosed me and had me on all kinds of medications, which I did
not need.

My question is:  does an insurance company (via my social security
number or DOB only) have access to finding those lab tests or any of
my lab works.  I have always paid my doctor in cash/check/credit card.
 My doctor?s office has indicated that, if asked, my last 3 visits
were for sinus issues & the flu (which is true).  But if I don't list
his office, or any doctor?s office information on my application, can
the insurance company find this information? And if so, how? And if
so, do I have access to finding out what they have access to?

The MIB (Medical Information Bureau) is the source of medical
information for many insurance companies, etc.  The good thing is that
you can request a copy of your record and if they have one for you
--you're given the right to change anything that is incorrect. So they
say.
http://www.mib.com/
Good luck.  I suppose we should all investigate this website for ourselves.

An interesting site, however on their website it states:  

"If you have not applied for individually underwritten life, health,
or disability insurance during the preceding seven year period, MIB
will not have a record on you."

It's been 11 years for me.

Thanks for the comment though !

1) Insurance companies will more than likely not have access to that
information.  There is a chance (probably around 5%) that they could
find that information out.  2) From what you've described, an
insurance company would not think those conditions to be bad risks. 
It's not like you've had 3 liver transplants and a kidney
transplant... even with those on your record, you're still a clean
individual.

PS... the person in the last answer was faulty in a few things they
said.  The insurance company will not demand benefit payments be
returned to them in the case that they find out you're lying.  What
they'll do is simple... let's say that you lied and your premium was
300/ month for health insurance.  Transversely, had you not lied, your
premium would have been 700/month.  The insurance company will try to
surcharge you the rate that you should have been paying the entire
time.  In the example above, the company will TRY to collect an extra
400 dollars for every month that you should have been paying more. 
TC'YA